Study On Urea Formaldehyde Resin Based Carbon Using As Electrode Materials Of Electrochemical Capacitors

Electrochemical capacitor is a new electric energy storage device which has notonly much more energy than conventional capacitors, but also much higher powerdensity than batteries. The physical and chemical characteristic of electrode materialsis the most important factor that influences electrochemical performance ofelectrochemical capacitors. Recent years, research and development of new electrodematerials with excellent electrochemical performance have attracted much attention inthe energy storage area.In this dissertation, pore structure controlling and optimization of carbon materialaccording to different urea/formaldehyde molar ratio and different activated time werestudied in detail. Moreover, electrochemical performance of urea-formaldehyde basedporous carbons were also been investigated. The properties of urea-formaldehydebased carbon material and activated carbon materials were investigated by N2adsorption, SEM, TEM, XRD, XPS, element analysis and so on. The electrochemicalperformance of electrode materials and prepared electrochemical capacitors weretested by electrochemical measurements such as constant current charge-discharge,cyclic voltammogram. The relationship between the pore structure of carbon electrodematerial and its electrochemical performance were investigated. In this paper, mainworks have been done as following:Urea and formaldehyde were used as raw materials to prepare microspheresunder certain concentration of catalyst-formic acid. In order to design carbonaceousprecursors with different pore structure, three urea and formaldehyde molar ratioswere used. And then the precursors were carbonized to prepare spherical carbons withhigh mesoporosity and high surface area. The effects of urea formaldehyde molarratio on the pore structure, surface and electrochemical performance weresystematically studied. The results showed that the capacitance of the sampleUF1.6-C2, which owns specific surface area as609m2/g and pore volume as1.15cm3/g can reach to205F/g in30wt%KOH at the current density50mA/g. In addition,it also showed good cyclic properties. The urea-formaldehyde based activated spherical carbons were successfullyprepared through physical activation process for the first time and carbon dioxidewere used as activating agents. The effects of different activation time on the porestructure and electrochemical performance of activated carbons were studied in detail.The results showed that the capacitance of the sample UF1.6-C2-A4, which ownsspecific surface area more than1700m2/g can reach to255F/g in30wt%KOH at thecurrent density50mA/g.